AQA GCSE Physics

Revision Notes

7.3.4 Microphones

Higher Tier Only

Moving-Coil Microphone

  • Microphones convert sound waves into electrical current
  • A moving coil microphone works using the principles of the generator effect

moving-coil-microphone, IGCSE & GCSE Physics revision notes

The moving coil microphone

  • When sound waves reach the microphone, the pressure variations cause the diaphragm to vibrate
  • This in turn causes the coil to move back and forth, through the magnetic field produced by the magnet
  • As it does so, the coil cuts through the field lines
    • This induces a potential difference in the coil
  • The potential difference will be alternating because the coil is continually changing direction due to the vibrations of the diaphragm

Exam Tip

Microphones and loudspeakers look very similar, but they do very different things.

When tackling a question on either of them, make sure you are writing about the right one!

You might be expected to give the above explanation – you will learn it better if you understand it!

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Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.

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